Clausiuraloceras mechetlense, a New Ammonoid Species from the Kungurian of the Southern Cisuralian Region

Abstract

A new species, Clausiuraloceras mechetlense sp. nov., is described from the lower part of the Kungurian (pnevi Zone) of the Mechetlino-3 (quarry) section, which is a candidate for the Global Boundary Stratotype Section and Point (GSSP) of the Artinskian-Kungurian Boundary. The species has a set of characters in the sutural outline, shell shape and ornamentation, the appearance of which indicates the beginning of a new stage in the morphogenesis of paragastrioceratids of Cisuralia. Beds with C. mechetlense are recognized in the southern Cisuralian Region, the lower boundary of which is placed at the base of the Kungurian.